This program is designed to allow one to convert the Open WLAN Map Database to many more, much smaller Grid-Square Databases.
Both formats are the same CSV. One just is one huge file, while the other is many smaller files.
KLUDGE ALERT!
Yes, this is a kludge. It may get better. It does the job.
Please, be a good citizen. Do not download the database from the Open WLAN Map project more than once a week. It is updated nightly, so doing it multiple times a day would be counter productive. As it is hosted generously by an individual, do not abuse the system. Go as long as you can between downloads. Certainly do not download it more than any guidelines given on the project's website. Thank you!
Place this script and the db.csv file from the Open WLAN Map project into the same directory. It should not contain any other files/data.
Run the script, without any arguments. It will create a gsdb directory and place the appropriate data in the appropriate files within that directory.
These files will be 3 levels of grid-square information. At my latitude, these are just about 1 mile by .3 miles in size. This keeps the data small and manageable for such uses as my "Open WLAN Map Public Data Visualizer."
This is F/OSS. I will provide some support for this, but don't expect too much for no money! If you want to help fix something or add a feature, I am very interested in hearing from you.